You have a 35 year mortgage, which means that you will be paying even less off in 5 years than a 25 year mortgage.

Any particular reason for this choice?

As you have mentioned saving, I would suggest that you will struggle to generate as much interest as you are paying on your mortgage, and I would look to make overpayments on the mortgage (checking that it is acceptable - usually up to 10% a year), which would save you the interest (5.99%).

A rough indication for a 25 year mortgage would be that you would have paid off just under 10% in the first 5 years. However the first 5 of a 35 year term is far less. Closer to the 4 or 5% you estimate.

You are only paying about 50 of the montly payment as repayment in month 1.

At the end of Year 5:

beginning balance (of prev. year) £60,169.91

interest paid in year 5 £3,585.46

capital repaid £689.35

ending balance £59,480.56

Compared to the 25 year mortgage which will cost an extra £45 a month (£2760):

Outstanding at end of year 5: £56,244.44 (3236.12 less)

So paying the extra 46 pounds a month would save you an extra 500 over the 5 year period.

HTH

Sparky.